Reciprocating pump



March' 22 1927.

Y 1N VENTOR CHAPL'S FPEDEP/C: SHEPWOQD C. F. SHERWOOD RECIPROCATING PUMP Original Filed Jan. 19. 1921 ATTORNEY I Patented Mar. 22, 1927.

' UNITED sTA'rEs PATENT oEFlcE.

RECIPROCATING PUMP.

Application led January 19, 1921, Serial No. 438,355.' Renewed March 25, 1926.

This invention relates to liquid pumps of the reciprocating type.. The object is to produce a pump the vsliding' surfaces 'of which will have a low coefficient of friction and at the same time will be resilient and non-corrosive.

e Rubber, if kept vvet, has a surprisingly low coefiicient of friction and I find that it can be successfully Vemployed in the construction of walls of a cylinder or piston of a pump and is well suited for use in pumps handling liquids which contain sand or def tritus in" considerable quantities or which contain corrosive substances., v

The present invention, is not concerned with the'iparticular method or manner of applying the rubber material to the cylinder walls or piston, and the laccompanying drawings are to be considered as-merely il lustrative of one way of'carrying' qut my invention. l Fig. 1 shows a Central ...sectional view of a conventional type of pump wherein the cylinder walls are lined with rubber and the body of the piston hasa covering 'of rubber.

F ig. 2 shows a similar view of a pump inwhich the cylinder walls only are lined with rubber and the pistonis of the usual metal construction.

" AThe pump herein shown includes aY cylinder l0, reciprocating piston 11, intake valves 12 and outlet valves 13.

In Fig. 1 the cylindervis provided with a lining 14 of vulcanized rubber and the body o'f the piston is provided with a rubber covering 15. In Fig. 2 the cylinder only carries the rubber friction surface.

The coefficient of friction of rubber against rubber or rubber against metal. `when the rubber is kept wet is suflciently low to permit of its practical use in a pump of this character. As is well known, 'rubber is non-corrosive and `its resilience or yielding qualities make it impossiblefor sand or otherl detritusto cause anv' great wear of the rubber.V Therefore rubsort.

ber used in the construction of cylinder or piston Walls will make the pump ideally suited for use in pumping acids or corrosive substances and also for pumping Water or other liquids which contain aconsiderable' quantity of sand or detritus. The rubber is suiiiciently resilient and yielding to allow the sand particles to embed themselves therein so that there can be no undue Wearing or scoring of the sliding surfaces.

The fit between the rubbing or slidingwsurfaces when rubber is used can be made just as tight as desired without danger of undue Wearing or heating ofthe rubber. Consequently it is possible to maintain high pressuresor vacuums in a pump of this Inasmuch as the pump is used only for handling liquids the rubber friction surfaces will be kept damp at all times and the-coeiiicient of friction will be kept within proper limits.

Having thus sliding contact with the piston.

2. A liquid pump including a cylinder,a reciprocating piston, a lining for the Walls of the cylinder formed of rubber and a covering for. the body of the pistonformed described my invention, what I claim and desire to secure by Letters Pat-- for also of rubber, the rubber lining of the cylinder being in sliding contact with the rubber on the piston.

3. In a reciprocating pump. an outer me,

tallic cylinder and an inner. `lining therefor made up of a sleeve of compressible wear resisting material.

4. In a pump. a cylinder 0f rigid material, a sleeve {it-ting closelv therein made up of'aJ compiessible material such as rubber,

and a reciprocating piston adaptedjo fit n closely against said sleeve.

CHARLES FREDERIC sHERvvooi). 

